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‘Game-changing’ four-stroke hits new heights

Tue 10 Oct 2017

‘Game-changing’ four-stroke hits new heights
The MAN 45/60 CR offers significant improvements in fuel consumption over its predecessor

A new engine launch by MAN is inevitably big news, so the unveiling of a flagship designed to start a whole new family is even bigger

As one waited for the official announcement of MAN Diesel & Turbo’s latest four-stroke engine in Augsburg, Germany, it was clear that a theme was developing. The motif on the floor was that of a chessboard, while giant chess pieces adorned the various squares. Meanwhile the accompanying signage bellowed ‘MAKE YOUR MOVE NOW!’

Eventually, all became clear: this new launch, the company believes, is ‘The Game Changer.’

The launch in question was the MAN 45/60CR, billed as the successor to MAN’s 48/60CR engine in the company’s 4x line of high-performance diesel engines. This will initially be available as 12V and 14V versions that boast power outputs of 15,600 and 18,200 kW respectively, with inline versions following at a later stage. For land-based power generation applications, MAN has developed the maximum power version, the 20V45/60 with 26 MW.

Compared with its predecessor, the new engine offers an SFOC reduction from 173 to 166 g/kWh, while providing a power increase from 1,200 to 1,300 kW per cylinder.

Alexander Koerber, product manager for the new engine, said this represents a gain in efficiency of 4-6% over its predecessor in marine applications.

The ‘game-changing’ aspect of the new vessel, though, lies in its fuel consumption, which D Sokrates Tolgos, MAN’s head of sales for cruise and ferry, described as setting “new standards in efficiency” and delivering “the highest power output in its class.”

In fact, continuing the game-changing theme (albeit perhaps unwittingly) Mr Tolgos said of the new engine while speaking to Marine Propulsion: “The 45/60CR offers a unique competitive advantage in that when it comes to SFOC (specific fuel oil consumption), it is without competition. This engine is playing in a new league and – for the time being – it is playing entirely on its own.”

Mr Tolgos’s job title is significant because this engine is aimed primarily at the cruise market, with ferries, dredgers and ropax and roro vessels also targeted. He said: “The focus is mainly on the cruise sector, which is why it makes sense for us to launch now. Most of the cruise yards are full and we are already talking with companies about projects that will be delivered in 2021 and 2022.”

The fuel consumption of the new engine is clearly a significant factor in its attraction for the environmentally, cost- and publicity conscious cruise sector. Clearly, the company is making big claims for the new engine’s prowess in this regard, and the figures would appear to back them up.

MAN’s figures show that, based on a representative load profile of a cruise vessel (between 50% and 85%), a ship operating with a 45/60CR engine would enjoy a fuel-oil cost benefit of as much as 5-12% in comparison with a vessel powered by a competitor engine. For a cruise vessel of around 120,000-150,000 gt, with 60-65 MW of installed power (and an assumed fuel price of US$591/tonne), this translates into annual savings of between US$1M and US$2.8M per year (calculated at 4,500 hrs).

By aiming at the cruise sector, MAN is essentially backing the current cruising boom to continue for the forseeable future. When questioned on this, Mr Tolgos told Marine Propulsion: “The cruise sector is ideal for this engine. They need high efficiency and low consumption, and we can deliver that.” He confirmed that MAN believes that the cruise boom would largely be driven by the growing Asian market.

Given this concentration on the cruise sector, it seemed somewhat anomalous that the engine is currently only available in a diesel version.

But given that the sectors in question are increasingly moving to LNG and alternative power sources, is this the time to be launching a diesel engine aimed at these sectors? In answer, Mr Tolgos said: “There will be a dual-fuel version of this engine, but I cannot give a timeframe.”

Speaking to Marine Propulsion at the launch, Mr Tolgos said he did not believe that the launch of a purely diesel engine to the environmentally conscious cruise market would prove problematic given the efficiencies available. “LNG is not a magic solution," he said. “It is still a fossil fuel, after all.”

Mr Tolgos continued: “This was always designed to be a family of engines. However, evaluations suggest that by 2030, 80% of engines will still be oil-based and we cannot afford to put all our eggs in one basket.”

Speaking to Marine Propulsion, launch attendee Jens Kohlmann, vice president for asset management at Carnival, appeared to confirm that the current lack of a dual-fuel option was not particularly problematic as far as his company was concerned. “We are certain that there will be a dual-fuel version of the engine available when we need it, so we are not worried,” he said.

The fuel savings are achieved by a number of factors in the engine’s design. MAN product development manager Alexander Koerber explained: “The new engine is the same size as the 48/60CR, but with hugely improved SFOC. How did we achieve that? By starting from scratch with this engine and using state-of-the-art technologies.”

The first of these technologies to come under scrutiny was MAN’s common rail injection system, which was updated and adapted to the specific needs of the engine, and optimised using a new version of MAN’s mapping software, ECOMAP. This gives operators the flexibility to run an engine following different SFOC power characteristics, facilitating optimal efficiency at different load points.

Mr Koerber stated: “We did not really change the common rail system, we just optimised it and adjusted it for the higher engine speed. The benefits of common rail technology are that you always have an optimum relationship between flame temperature and emissions, and you can control the timing and rate of injection.”

Another key technology in the achievement of this low SFOC was two-stage turbocharging. Mr Koerber explained: “Two-stage turbocharging draws more energy from the exhaust gas as you’re using the energy twice. Also, two-stage turbochargers can be optimised in terms of adjusting for higher pressure ratios, meaning greater efficiency.”

But despite the turbocharging being two-stage, load pick-up behaviour is the same as for the single-stage turbocharged 48/60CR engine. This means operators profit from maximised peak pressure and optimal utilisation of the Miller cycle.

Simulation was used extensively in the development of the engine. A complete simulation was made of the entire engine, while combustion itself was optimised by simulating the process in computational fluid dynamics. In addition, finite elements analysis was used to optimise the engine’s mechanical strength and vibration behaviour. MAN then put the power unit to the test on the world’s largest four-stroke, single-cylinder test engine, and started the experimental optimisation and validation phase.

The modular design and relatively small footprint for its power means that the engine is able to simplify installation and allow for a smaller engineroom. That said, the 12 V version comes in at seven tonnes heavier than the comparable 48/60CR. Mr Koerber notes that the extra weight is due to reinforcements to the engine base, and the addition of the two-stage turbocharger.

The 45/60CR features MAN’s latest release of its proprietary engine-control system. SaCoS 5000 represents a comprehensive upgrade and expansion of the original system’s capabilities.

The development of SaCoS 5000 is a response to the increasing complexity and exponential growth in functionality of modern engines. The main benefit of SaCoS 5000 is its function-oriented architecture that makes it ultra-flexible and enables more bespoke solutions. This means that MAN can add different options to a standard system for the individual customer, such as cylinder-pressure measurements, crankcase monitoring, and injection-system leakage monitoring.

Furthermore, the new system is capable of handling complex functions that demand a lot of control and calculation resources. Such functions include cylinder balancing and the company’s own ECOMAP function, which grants operators the flexibility to run an engine following different SFOC power characteristics. This facilitates optimal efficiency at different load points.

The new SaCoS lays the foundation for the next generation of MAN Diesel & Turbo’s digital products. Chief digital officer Audi Lucas explained: “SaCoS 5000 is a key element of our digitisation strategy, and enables a new line of digital solutions that will be available from the year 2018 on. This will offer distinct benefits to our customers. Those solutions will feature a new and modern security design, with both active and passive defenses, while continuous upgrades will ensure that the system evolves as needs change. They will also allow hybrid local and cloud-based analytics across a customer’s fleet and a completely new and revolutionary way to exchange data in real time with all partners necessary. With the introduction of SaCoS 5000, we take a first step into that digital future.”

 

MAN 45/60CR specifications

Bore

450 mm

Stroke

600 mm

Cylinder configuration

6-10 inline (L); 12-20 V

Power output per cylinder

1,300 kW

Speed

600 rpm

Power range

7,800-18,200 kW

BMEP

27.2 bar

Specific fuel oil consumption

L: 167 g/kWh; V:166 g/kWh